Circularly polarized log-periodic antenna based on radiation oscillator rotation

Abstract

The invention discloses a circularly polarized log-periodic antenna based on radiation oscillator rotation, belongs to the technical field of antenna engineering, and solves the problem of how to design a circularly polarized log-periodic antenna with wide bandwidth, low profile and simple structure. A parallel collection line is taken as an axis, and corresponding circularly polarized characteristics are formed by rotating a plurality of groups of radiation oscillators by a certain angle; the antenna is only provided with a group of radiation oscillators according with the regular change of a log-periodic antenna, has no main and auxiliary oscillators, has a simpler structure, is easy to implement, and forms a circular polarization effect by rotating the radiation oscillators to a certain phase and the phase difference between electromagnetic waves from each oscillator to the zero point of the antenna. And the log-periodic antenna can obtain good impedance bandwidth and 3dB axial ratio bandwidth in a working frequency band.

Description

Technical Field

[0001] The invention belongs to the technical field of antenna engineering, and relates to a circularly polarized logarithmic periodic antenna based on the rotation of a radiation oscillator. Background Art

[0002] The log-periodic antenna is a non-frequency-variant ultra-wideband antenna with a self-similar structure. Its electrical performance can remain basically unchanged within a frequency band of 10:1 or even wider. Conventional log-periodic antennas are fed by coaxial cables, and the feeding point is located on the short-side dipole. It has the advantages of low profile, small gain fluctuation within the band, symmetrical radiation pattern, simple structure, and easy processing. Therefore, it is widely used in communications, direction finding, electronic countermeasures and other fields.

[0003] However, due to the rapid development of modern wireless communication systems and the increasing complexity of the electromagnetic environment, the system has put forward more stringent requirements for antenna polarization. At present, antenna polarization can be divided into three categories: circular polarization, elliptical polarization and linear polarization. Compared with linear polarization and elliptical polarization antennas, circular polarization antennas have better performance, such as suppressing multipath fading, being able to communicate and interconnect with any linear polarization antenna, and being able to receive or radiate electromagnetic waves of any polarization. Therefore, they have been widely used in the fields of positioning, communication and navigation.

[0004] Common circular polarization designs for log-periodic antennas mostly use a dual-main-pole structure (corresponding to dual output ports). A bridge is usually used to convert one signal into two signals with a phase difference of 90°, and then connected to the dual ports of the antenna to achieve the circular polarization requirements of the antenna. This method is complex and bulky in structure, inconvenient to use and operate, and increases the cost of processing and use. There is also a structural phase shift method that does not require the addition of a 90° bridge, but the dual-main-pole structure is still used, resulting in a complex and bulky overall structure.

[0005] In the prior art, the Chinese invention patent application document "A Circularly Polarized Log-Periodic Antenna" with application publication number CN116565517A and application publication date August 8, 2023 provides a circularly polarized log-periodic antenna structure, which is equivalent to combining two groups of radiating oscillators that change according to the logarithmic periodic law in a vertically intersecting form. The corresponding main and secondary oscillator groups are similar in length, and the vertical relationship between the main oscillator and the corresponding secondary oscillator and the phase difference between the electromagnetic waves radiated to the zero point of the antenna form circular polarization.

[0006] The Chinese invention patent application document "A broadband circularly polarized log-periodic antenna" with application publication number CN107579338A and application publication date January 12, 2018, provides a broadband circularly polarized log-periodic antenna structure. The structure also adopts a vertical scheme for the main and secondary oscillators, but the length variation of the secondary oscillator does not conform to the law of log-periodic antennas. It forms a circular polarization effect through simple mode splitting between adjacent main and secondary oscillators.

[0007] The above two structures both have the problems of being complex and bulky in overall structure, difficult to process and complicated to operate. Summary of the invention

[0008] The technical solution of the present invention is used to solve the problem of how to design a logarithmic periodic circularly polarized antenna with wide bandwidth, low profile and simple structure.

[0009] The present invention solves the above technical problems through the following technical solutions:

[0010] A circularly polarized logarithmic periodic antenna based on the rotation of a radiating element, comprising: two first radiating elements (1), two second radiating elements (2), two third radiating elements (3), and two parallel set lines (4); the two parallel set lines (4) are arranged horizontally and in parallel along the y-axis direction, the two first radiating elements (1) are respectively connected to the left ends of the upper and lower parallel set lines (4), the axes of the length directions of the two first radiating elements (1) are parallel to each other, and the angles between the axes of the length directions of the two first radiating elements (1) and the z-axis are both 66°; the two second radiating elements (2) are respectively connected to the upper and lower left ends of the parallel set lines (4). The first radiator (1) is connected to the middle of the upper and lower parallel collection lines (4), the axes of the length direction of the two second radiators (2) are parallel to each other, and the angles between the axes of the length direction of the two second radiators (2) and the z-axis are both 30°; the second radiators (3) are connected to the middle of the upper and lower parallel collection lines (4), the axes of the length direction of the two third radiators (3) are parallel to each other, and the angles between the axes of the length direction of the two third radiators (3) and the z-axis are both 90°; the ratio of the lengths of the first radiator (1), the second radiator (2) and the third radiator (3) is 1:K:K 2 The ratio of the horizontal spacing between the first radiation vibrator (1), the second radiation vibrator (2), and the third radiation vibrator (3) is also 1:K:K 2 .

[0011] Furthermore, the parallel set line (4) is fed at one end close to the third radiating element, and the cross-feeding of the logarithmic periodic antenna is realized through the parallel set line (4) structure. The electromagnetic wave energy input from the feeding point is transmitted along the parallel set line (4) from the third radiating element end to the first radiating element end. During the transmission process, each radiating element is excited in turn to form end-to-end radiation, and the maximum radiation direction is from the first radiating element to the third radiating element. During the electromagnetic wave radiation process, there is a phase difference between the electromagnetic waves from the second radiating element (2) and the third radiating element (3) to the antenna zero point. At the same time, when the electromagnetic wave propagates from the third radiating element end along the parallel set line (4) to each group of radiating elements, the radiating element is excited and radiates along the air, and the radiating element forms the phase of the electromagnetic wave in space through the rotation angle. When the generated electromagnetic wave phase is integrated to form a phase difference of 90°, the circular polarization characteristic of the antenna is realized.

[0012] Furthermore, the first radiating vibrator (1), the second radiating vibrator (2), the third radiating vibrator (3), and the parallel set of lines (4) are all preformed metal columns.

[0013] Preferably, the material of the preformed metal column is copper.

[0014] Preferably, the radius of the preformed metal column is 3 mm.

[0015] Preferably, the value range of K is 0.8 to 0.95.

[0016] Preferably, the length of the first radiating vibrator (1) is 100 mm, the length of the second radiating vibrator (2) is 85 mm, the length of the third radiating vibrator (3) is 72.25 mm, and the length of the parallel set line (4) is 104.5 mm.

[0017] Preferably, the distance between the horizontal axis of each of the parallel set lines (4) and the horizontal central symmetry line of the antenna is 3.8 mm.

[0018] The advantages of the present invention are:

[0019] The circularly polarized log-periodic antenna structure based on the rotation of the radiating element proposed in the present invention is to obtain a circularly polarized log-periodic antenna with a simpler and more sophisticated structure. Based on the performance advantages of wide bandwidth and low profile existing in the self-similar structure of the traditional log-periodic antenna, a plurality of groups of radiating elements are rotated by a certain angle with parallel collective lines as axes to form corresponding circular polarization characteristics. The log-periodic antenna can obtain good impedance bandwidth and 3dB axial ratio bandwidth in the working frequency band. Compared with the current log-periodic antenna circularly polarized structure, it is simpler and easier to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A schematic diagram of the three-dimensional structure of a circularly polarized log-periodic antenna based on the rotation of a radiation element according to the first embodiment of the present invention;

[0021] Figure 2 A front view of the three-dimensional structure of a circularly polarized log-periodic antenna based on the rotation of a radiation element according to the first embodiment of the present invention;

[0022] Figure 3 A top view of the three-dimensional structure of a circularly polarized log-periodic antenna based on the rotation of a radiation element according to the first embodiment of the present invention;

[0023] Figure 4 A side view of the three-dimensional structure of a circularly polarized log-periodic antenna based on the rotation of a radiation element according to the first embodiment of the present invention;

[0024] Figure 5 This is a graph of the S11 parameter of the circularly polarized log-periodic antenna based on the rotation of the radiating element according to the first embodiment of the present invention;

[0025] Figure 6 This is an axial ratio curve diagram of the circularly polarized log-periodic antenna based on the rotation of the radiation element according to the first embodiment of the present invention;

[0026] Figure 7 The Phi=90° radiation pattern of the circularly polarized log-periodic antenna based on the rotation of the radiating element at 1.25 GHz according to the first embodiment of the present invention;

[0027] Figure 8 The Phi=0° radiation pattern of the circularly polarized log-periodic antenna at 1.25 GHz based on the rotation of the radiating element according to the first embodiment of the present invention;

[0028] Fig. 9 The Phi=90° radiation pattern of the circularly polarized log-periodic antenna at 1.3 GHz based on the rotation of the radiating element according to the first embodiment of the present invention;

[0029] Fig.10 The Phi=0° radiation pattern of the circularly polarized log-periodic antenna at 1.3 GHz based on the rotation of the radiating element according to the first embodiment of the present invention;

[0030] Fig.11 The Phi=90° radiation pattern of the circularly polarized log-periodic antenna at 1.4 GHz based on the rotation of the radiating element according to the first embodiment of the present invention;

[0031] Fig.12 This is the Phi=0° radiation pattern of the circularly polarized log-periodic antenna at 1.4 GHz based on the rotation of the radiating element according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0034] Embodiment 1

[0035] like Figures 1 to 4 As shown, the circularly polarized log-periodic antenna based on the rotation of the radiating element of the embodiment of the present invention comprises: two first radiating elements (1), two second radiating elements (2), two third radiating elements (3), and two parallel set lines (4); the first radiating elements (1), the second radiating elements (2), the third radiating elements (3), and the parallel set lines (4) are all preformed metal columns; preferably, the radius of the preformed metal columns is 3 mm and the material is copper.

[0036] The two parallel set lines (4) are arranged horizontally and in parallel along the y-axis direction, and the two first radiating vibrators (1), the two second radiating vibrators (2), and the two third radiating vibrators (3) are arranged alternately at a certain distance from left to right along the y-axis direction and are respectively connected to the upper and lower parallel set lines (4), as follows:

[0037] The two first radiating vibrators (1) are respectively connected to the left ends of the upper and lower parallel collection lines (4), the axes of the two first radiating vibrators (1) in the length direction are parallel to each other, and the angles between the axes of the two first radiating vibrators (1) in the length direction and the z-axis are both 66°; the two second radiating vibrators (2) are respectively connected to the middle of the upper and lower parallel collection lines (4), the axes of the two second radiating vibrators (2) in the length direction are parallel to each other, and the angles between the axes of the two second radiating vibrators (2) in the length direction and the z-axis are both 30°; the two third radiating vibrators (3) are respectively connected to the middle of the upper and lower parallel collection lines (4), the axes of the two third radiating vibrators (3) in the length direction are parallel to each other, and the angles between the axes of the two third radiating vibrators (3) in the length direction and the z-axis are both 90°.

[0038] The length ratio of the first radiation vibrator (1), the second radiation vibrator (2) and the third radiation vibrator (3) is 1:K:K 2 The ratio of the horizontal spacing between the first radiation vibrator (1), the second radiation vibrator (2), and the third radiation vibrator (3) is also 1:K:K2 , the value range of K is 0.8~0.95; preferably, K is 0.85, at this time, the length of the first radiating element (1) is 100mm, the length of the second radiating element (2) is 85mm, the length of the third radiating element (3) is 72.25mm, the length of the parallel set line (4) is 104.5mm, and the distance between the horizontal axis of each parallel set line (4) and the horizontal center symmetry line of the antenna is 3.8mm.

[0039] The working principle of the antenna is as follows:

[0040] Feeding is provided at one end of the parallel collection line (4) (close to the end of the short radiating element (third radiating element) of the logarithmic periodic antenna), and cross-feeding of the logarithmic periodic antenna is realized through the parallel collection line (4) structure. The electromagnetic wave energy input from the feeding point is transmitted along the parallel collection line (4) from the short radiating element (third radiating element) end to the long radiating element (first radiating element) end. During the transmission process, each radiating element is excited in turn to form end-to-end radiation, and the maximum radiation direction is from the long radiating element (first radiating element) to the short radiating element (third radiating element). During the electromagnetic wave radiation process, there is a phase difference between the electromagnetic waves from the second radiating element (2) and the third radiating element (3) to the zero point of the antenna. At the same time, when the electromagnetic wave propagates from the short radiating element (third radiating element) end along the parallel collection line (4) to each group of radiating elements, the radiating element is excited and radiates along the air, and the radiating element forms the phase of the electromagnetic wave radiated in space by rotating a certain angle. When the generated electromagnetic wave phase is integrated to form a phase difference of 90°, the circular polarization characteristic of the antenna is realized.

[0041] The antenna of this embodiment has only one group of radiating elements that change in accordance with the law of logarithmic periodic antenna, without distinction between main and auxiliary elements, and has a simpler structure and is easier to implement. At the same time, a circular polarization effect is formed by rotating the radiating elements to a certain phase and the phase difference between the electromagnetic waves from each element to the zero point of the antenna.

[0042] Figure 5 This is a curve diagram of the S11 parameter of the circularly polarized logarithmic periodic antenna based on the rotation of the radiation oscillator in this embodiment after electromagnetic simulation. It can be seen that the reflection coefficient |S in the 1.19 GHz-2.21 GHz frequency band 11 |All are less than -10dB, and the consistency is good.

[0043] Figure 6 This is an axial ratio curve diagram of the circularly polarized log-periodic antenna based on the rotation of the radiating oscillator of this embodiment after electromagnetic simulation. It can be seen that the axial ratio coefficients in the 1.23GHz-1.42GHz frequency band are all less than 3dB, which shows that circular polarization can be achieved in this frequency band and the circular polarization requirements are met.

[0044] Figures 7 and 8 This is the radiation pattern at 1.25 GHz of the circularly polarized log-periodic antenna based on the rotation of the radiation element of this embodiment after electromagnetic simulation. It can be seen that the antenna forms a good left-handed polarization.

[0045] Figures 9 and 10 This is the radiation pattern at 1.3 GHz of the circularly polarized log-periodic antenna based on the rotation of the radiation element of this embodiment after electromagnetic simulation. It can be seen that the antenna forms a good left-handed polarization.

[0046] Figure 11 to Figure 12 This is the radiation pattern at 1.4 GHz of the circularly polarized log-periodic antenna based on the rotation of the radiation element of this embodiment after electromagnetic simulation. It can be seen that the antenna forms a good left-handed polarization.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circularly polarized log-periodic antenna based on the rotation of a radiating element, characterized in that: include: Two first radiating vibrators (1), two second radiating vibrators (2), two third radiating vibrators (3), and two parallel set lines (4); the two parallel set lines (4) are arranged horizontally and in parallel along the y-axis direction; the two first radiating vibrators (1) are respectively connected to the left ends of the upper and lower parallel set lines (4); the axes of the length directions of the two first radiating vibrators (1) are parallel to each other; the angles between the axes of the length directions of the two first radiating vibrators (1) and the z-axis are both 66°; the two second radiating vibrators (2) are respectively connected to the upper and lower parallel set lines (4) The axes of the length direction of the two second radiating vibrators (2) are parallel to each other, and the angles between the axes of the length direction of the two second radiating vibrators (2) and the z-axis are both 30°; the two third radiating vibrators (3) are respectively connected to the middle of the upper and lower parallel collection lines (4), the axes of the length direction of the two third radiating vibrators (3) are parallel to each other, and the angles between the axes of the length direction of the two third radiating vibrators (3) and the z-axis are both 90°; the ratio of the lengths of the first radiating vibrator (1), the second radiating vibrator (2) and the third radiating vibrator (3) is 1:K:K 2 The ratio of the horizontal spacing between the first radiation vibrator (1), the second radiation vibrator (2), and the third radiation vibrator (3) is also 1:K:K 2 .

2. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 1, characterized in that: Feeding is performed at one end of the parallel collection line (4) close to the third radiator, and cross-feeding of the logarithmic periodic antenna is realized through the parallel collection line (4) structure. The electromagnetic wave energy input from the feeding point is transmitted along the parallel collection line (4) from the third radiator end to the first radiator end. During the transmission process, each radiator is excited in turn to form end-to-end radiation, and the maximum radiation direction is from the first radiator to the third radiator. During the electromagnetic wave radiation process, there is a phase difference between the electromagnetic waves from the second radiator (2) and the third radiator (3) to the antenna zero point. At the same time, when the electromagnetic wave propagates from the third radiator end along the parallel collection line (4) to each group of radiators, the radiators are excited and radiate along the air, and the radiators form the phase of the electromagnetic wave in space through the rotation angle. When the generated electromagnetic wave phase is integrated to form a phase difference of 90°, the circular polarization characteristic of the antenna is realized.

3. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 1, characterized in that: The first radiating vibrator (1), the second radiating vibrator (2), the third radiating vibrator (3), and the parallel collection lines (4) are all preformed metal columns.

4. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 3, characterized in that: The material of the preformed metal column is copper.

5. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 3, characterized in that: The radius of the preformed metal column is 3 mm.

6. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 1, characterized in that: The value range of K is 0.8~0.

95.

7. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 6, characterized in that: The length of the first radiating vibrator (1) is 100 mm, the length of the second radiating vibrator (2) is 85 mm, the length of the third radiating vibrator (3) is 72.25 mm, and the length of the parallel set line (4) is 104.5 mm.

8. The circularly polarized log-periodic antenna based on the rotation of the radiation element according to claim 1, characterized in that: The distance between the horizontal axis of each parallel set of lines (4) and the horizontal central symmetry line of the antenna is 3.8 mm.

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